The present invention relates to closures for containers, and more particularly to a composite plastic closure for bottles.
The advantages of plastic composite closures for use on bottles and like containers have been recognized in recent years, and various attempts have been made of perfecting a suitable closure capable of effectively sealing a container. Parent application Ser. No. 270,241 discloses a composite plastic closure including a plastic shell or cap, and a plastic sealing liner. Means for retaining the liner within the cap include an annular lip extending inwardly of the cap which engages an annular sealing bead portion of the liner. Liner retention may be further provided by a plurality of pedestals or projections which extend integrally from the inner surface of the top wall portion of the plastic cap. Portions of that application not inconsistant with the present disclosure are incorporated herein by reference.
Effective sealing liner retention within the plastic cap of the closure poses a problem where the container to which the closure is applied has contents, such as a carbonated beverage, which include a gaseous medium. Migration of the gas in the container through the sealing liner may tend to dislodge the liner from the cap, thereby detracting from the effective sealing capabilities of the closure. Thus, a composite closure suited for use on a container which has contents containing a gaseous medium must be designed so that the sealing liner of the closure is held in a position to effect proper sealing.
The present invention improves upon plastic composite closures heretofore known by providing a liner retention arrangement which maintains the sealing liner in position to effect proper sealing.